As a new surge of killings erupted Monday in Homs, Syria, the United States shuttered its embassy in Damascus, citing security problems. British Foreign Secretary William Hague also dialed back relations with what he called a "doomed" and "murdering" regime. Ray Suarez reports.

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RAY SUAREZ:

The chaos deepened in Syria today. The military rained artillery fire on a rebellious city, as the U.S. and other countries began withdrawing key officials.

Diplomats were leaving Damascus today. The United States shuttered its embassy and pulled out Ambassador Robert Ford and 17 other staffers, citing worries about security.

And in London.

WILLIAM HAGUE, British foreign secretary: In parallel, I have today recalled to London our ambassador in Damascus for consultations.

RAY SUAREZ:

British Foreign Secretary William Hague dialed back relations with what he called a doomed and murdering regime.

But inside Syria, a new surge of killing. Video from Homs captured the chaos at a makeshift clinic after a third day of shelling by the Syrian army. The opposition said at least 50 people were killed in Homs today, and human rights groups reported as many as 200 died there on Saturday, the worst one-day toll since the uprising began last March.

The crackdown intensified even as Russia and China vetoed a U.N. Security Council resolution calling for President Bashar al-Assad to step down.

Western condemnation of the vetoes kept coming today, from London . . .

WILLIAM HAGUE:

The human suffering in Syria is already unimaginable and is in grave danger of escalating further. The position taken by Russia and China has regrettably made this more likely.

RAY SUAREZ:

. . . and from Paris, where French President Nicolas Sarkozy branded the vetoes a scandal.

But U.S. Secretary of State Hillary Clinton insisted Sunday in Bulgaria, that's not the end of it.

SECRETARY OF STATE HILLARY RODHAM CLINTON:

Faced with a neutered Security Council, we have to redouble our efforts outside of the United Nations with those allies and partners who support the Syrian people's right to have a better future.

RAY SUAREZ:

In Moscow, though, Russian Foreign Minister Sergei Lavrov was making no apologies.

SERGEI LAVROV, Russian foreign minister (through translator): Some of the voices coming from the West assessing the results of the U.N. Security Council vote on the Syrian resolution are indecent, I would say, and border on hysterics.

RAY SUAREZ:

And Chinese officials took the same line in Beijing.

LIU WEIMIN, Chinese Ministry of Foreign Affairs (through translator): China actively participated in the draft version of the U.N. resolution. But, unfortunately, the proposing nation, despite major disputes among various countries, forced a vote. Our goal is to make sure that Syrians are spared from violent conflict and war, not to complicate the issue.

RAY SUAREZ:

In Washington, President Obama played down the likelihood of outside military action in an interview with NBC News.

PRESIDENT BARACK OBAMA:

I think it is very important for us to try to resolve this without recourse to outside military intervention, and I think that's possible.

And the Assad regime is feeling the noose tightening around them.

This is not going to be a matter of if; it's going to be a matter of when.

RAY SUAREZ:

And, as the barrage at Homs raged on, the rebel commander of the Free Syria Army agreed Assad will go, but he said there's no other road left except military action.